Response NS

[B3B8]

Hi Mika
I'm working with Slim3 and in your example I see an interesting model of design pattern to handle Response PSR-7 as a separated NS (ie /src/response/NotFoundResponse.php). In API apps a lot of controllers run same function with the same response (ie Item, Collection, bad validation, db errors etc.. - Don't Repeat Yourself) and I want to use a global class/trait to handle responses from controllers and I found something in this API skeleton. But I don't understand how to handle Response $response outsite controller. Is it the right way ?

Finally, in your Response NS, all __construct call parent with

$headers = (new Headers)->set("Content-type", "application/problem+json");

but the Http Headers is null; I try to separate it like this

$headers = new Headers();
$headers->set("Content-type", "application/problem+json");

and Http Headers are set correctly. It's a mistake ?
Thank you so much!

[tuupola]

You are correct it is a bug. It seems I have assumed Headers object is immutable. Thanks for the heads up!

[B3B8]

Mika can I ask you a tip to reduce the serialize lines and respective response ie

$app->post("/todos", function ($request, $response, $arguments) {
 [...]
    /* Serialize the response data. */
    $fractal = new Manager();
    $fractal->setSerializer(new DataArraySerializer);
    $resource = new Collection($todos, new TodoTransformer);
    $data = $fractal->createData($resource)->toArray();

    return $response->withStatus(200)
        ->withHeader("Content-Type", "application/json")
        ->write(json_encode($data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT));

$app->get("/todos/{uid}", function ($request, $response, $arguments) {
 [...]
    /* Serialize the response data. */
    $fractal = new Manager();
    $fractal->setSerializer(new DataArraySerializer);
    $resource = new Item($todo, new TodoTransformer);
    $data = $fractal->createData($resource)->toArray();

    return $response->withStatus(200)
        ->withHeader("Content-Type", "application/json")
        ->write(json_encode($data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT));

Start from todos routes methods, compliting my others API routes like todos with the same functions, I'll write the same serialize with the same response, so I think about "don't repeat yourself" principle and maybe with SLIM design pattern I can improve the code...Is it right use this schema or I'm just complicating myself? If it's worth, how can you rewrite it?
Thanks for your suggestion!

[tuupola]

You could extract serializing part to external facade class and it would save a couple of lines in the route. Calling the facade could look something like.

$data = (new SerializerFacade($todo, TodoTransformer::class))->toArray()

Downside is this would make code a bit harder to follow since you have to go see the source of the facade class to understand what is happening. It is always a fine line between optimising and readability.